1. Field of the Invention
The present invention relates to a securing device, and more particularly to a securing device that can fit with different bicycle front forks in different dimensions.
2. Description of Related Art
With reference to FIGS. 4 and 5, a conventional securing device (40) for holding a bicycle front fork (70) on a bicycle frame, such as a head tube (80) comprises a clamping sleeve (42), an upper pressing base (44), a lower pressing base (46) and a connecting tube (48). The clamping sleeve (42) is hollow and has a C-shaped cross section. The upper and lower pressing bases (44,46) are attached respectively to two ends of the clamping sleeve (42) and abut and press against the inner surface of the clamping sleeve (42).
The upper pressing base (44) has a through hole and an upper pressing surface (442) being conical and pressing against the inner surface at the top end of the clamping sleeve (42). The lower pressing base (46) has a threaded hole (464) and a lower pressing surface (462) being conical and pressing against the inner surface at the bottom end of the clamping sleeve (42). The threaded hole (464) is defined in the lower pressing base (46). The connecting tube (48) extends through the through hole in the upper pressing base (44) and the clamping sleeve (42) and has an outer thread engaging and screwed into the threaded hole (464) in the lower pressing base (46). The connecting tube (48) has a threaded hole (482) defined in the top of the connecting tube (48).
To connect the front fork (70) with the head tube (80) with the securing device (40), the securing device (40) is put into the front fork (70) via the top opening of the front fork (70), and the upper pressing base (44) abuts against the top of the front fork (70). The connecting tube (48) is then rotated, and the lower pressing base (46) is moved close to the upper pressing base (44), and the clamping sleeve (42) will be expanded by the conical pressing surfaces (442,462) to press against the inner surface of the front fork (70).
A pressing bolt (50) extends through a cap (52) and is screwed into the threaded hole (482) in the connecting tube (48), wherein the cap (52) abuts against the top of the head tube (80). Accordingly, the front fork (70) is securely but rotatably connected with the head tube (80) with the securing device (40).
However, because the clamping sleeve (42) of the conventional securing device (40) is metal, the expansion level of the clamping sleeve (42) is limited such that the clamping sleeve (42) cannot be applied for different head tubes with different sizes.
Additionally, the pressing surfaces (442,462) on the pressing bases (44,46) have a same obliquity and only lower pressing base (46) moves during the combination process, so a long travel of the lower pressing base (46) is needed for expanding the clamping sleeve (42) to a desired level. Consequently, the length of the clamping sleeve (42) has to be large enough for a long travel of the lower pressing base (46), and the volume of the convention securing device (40) is large.
To overcome the shortcomings, the present invention tends to provide a securing device to mitigate or obviate the aforementioned problems.